Pesticidal compositions and methods employing substituted oxirane compounds

ABSTRACT

Disclosed herein are substituted oxirane compounds corresponding to the formula ##SPC1## 
     Wherein X represents halogen; Z represents hydrogen, halogen, cyano or lower alkyl; R and R&#39; each independently represent hydrogen, halogen, cyano, nitro, alkoxy, trifluoromethyl, benzyloxy or lower alkyl, with the proviso that when R&#39; is hydrogen, R is other than hydrogen. The compounds are especially useful as pesticides in preventing germination of undesired plant seeds and controlling noxious weeds and fungal organisms and can be formulated to provide pesticidal compositions.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of my copendingapplication Ser. No. 61,848, filed Aug. 6, 1970, now abandoned.

BACKGROUND OF THE INVENTION

In recent years, the use of chemicals for controlling various biologicalforms has found widespread acceptance among many people. This isespecially true among agriculturalists interested in controlling fungaland terrestrial plants. For example, chemical compositions havepreviously been applied to the soil or to the foliage of fully developedplants, thereby destroying certain types of plants in a selective mannerand allowing others to continue their growth in a more favorableenvironment. This type of control, enabling certain plants to growfreely unhampered by competing noxious plants, has also been achieved bythe application of chemical compositions to the soil, which chemicalcompositions either prevent germination of undesirable seeds or destroythe emerging seedlings immediately after germination. Other dangersconfronting plant growth and crop yields occur in the form of plantdiseases. These threats to desirable plant life have been lessened bythe application of fungicides to the soil, foliage of the plants, andsurrounding atmosphere.

Very effective control and protection of desirable plant life istherefore possible through the use of chemicals formulated to provideprotection as selective herbicides and fungicides. However, allrequirements for effectiveness and selectivity among pesticides have notbeen satisfied. There are still many demands to satisfy amongagriculturalists and others, either for more effective pesticides withselectivity comparable to old pesticides, or for pesticides with adifferent selectivity.

SUMMARY OF THE INVENTION

This invention relates to pesticidal compositions and methods utilizingsubstituted oxirane compounds as active ingredients. According to thepresent invention, there are provided pesticidal compositions containingcompounds of the formula: ##SPC2##

Wherein X represents halogen; Z represents hydrogen, halogen, cyano orlower alkyl; R and R' each independently represent hydrogen, halogen,cyano, nitro, lower alkoxy, trifluoromethyl, benzyloxy or lower alkyl,with the proviso that when R' is hydrogen, R is other than hydrogen. Anadditional preferred class of compounds are those wherein R is hydrogenand R' is as previously defined. A preferred class of compounds arethose wherein R and R' each independently represent hydrogen, halogen,nitro, lower alkoxy, trifluoromethyl or lower alkyl, with the provisothat when R' is hydrogen, R is other than hydrogen. A further preferredclass of compounds are those wherein R and R' each independentlyrepresent hydrogen, halogen, trifluoromethyl or lower alkyl, with theproviso that when R' is hydrogen, R is other than hydrogen. Anespecially preferred class of compounds are those wherein R and R' eachindependently represent hydrogen, halogen or trifluoromethyl, with theproviso that when R' is hydrogen, R is other than hydrogen. A mostpreferred class of compounds are those where R represents hydrogen andR' represents halogen or trifluoromethyl.

Also provided herein are methods of controlling undesired fungalorganisms and weed growth by application of the compounds of thisinvention. At low application rates certain of the compounds are usefulas selective herbicides in desirable crops such as corn, cotton,soybeans, rice and the like.

As used herein, the term "lower alkyl" means saturated, monovalentaliphatic radicals, including straight and branched-chain radicals offrom 1 to about 4 carbon atoms, as illustrated by, but not limited to,methyl, ethyl, propyl, isopropyl, butyl, sec.-butyl and the like. Theterm "lower alkoxy" includes straight and branched-chain radicals offrom 1 to about 4 carbon atoms, as illustrated by, but not limited to,methoxy, ethoxy, propoxy, isopropoxy, butoxy, and the like. The term"halogen" represents bromine, chlorine, fluorine and iodine.

The substituted oxirane compounds of the present invention, hereinafterreferred to as "oxirane" compounds, are generally oils or crystallinesolids at room temperature which are soluble in the usual organicsolvents such as, for example, 1,2-dichlorobenzene, methylene chloride,chloroform and the like. They are readily prepared by the reaction of asubstituted styrene compound of the formula: ##SPC3##

wherein R, R', X and Z are as hereinbefore defined, with a suitablepercarboxylic acid reactant. Representative and suitable percarboxylicacids which can be employed in the preparation of the substitutedoxirane compounds include, for example, peracetic acid,trifluoroperacetic acid, perbenzoic acid and the like. In the presentinvention, buffer solutions of the acid reactants are preferablyemployed and are prepared by the use of a buffer agent, such as, forexample, sodium acetate, sodium benzoate and the like.

In carrying out the reaction, the percarboxylic acid reactant is added,dropwise or portionwise over a period of about 5-10 minutes, to thesubstituted styrene reactant. While the amounts of the reactants to beemployed are not critical, the reaction generally consumes the reactantsin the proportion of one mole of substituted styrene reactant to one ormore moles of percarboxylic acid reactant. A suitable ratio of reactantsis from about 1:1 to about 1:6 (substituted styrene:percarboxylic acid)and the employment of the reactants in a mole ratio of about 1:4 ispreferred. The reaction is allowed to proceed at a temperature betweenabout 20° and about 40°C. and is preferably maintained at roomtemperature. The pressure is not critical and is usually maintained atambient atmospheric pressure. The reaction mass is maintained for aperiod of time sufficient to assure substantial completion of thereaction, generally from about 12 to about 20 hours or longer. Recoveryof the product from the reaction mass is achieved by employingconventional procedures. Typically, the reaction mass is washed withwater and neutralized with a sufficient amount of base, e.g., sodiumcarbonate, before being evaporated to dryness under reduced pressure.

The desirable properties of the present products are inherent in thepure compounds; when highly selective properties are to be relied, thepurified compounds will be preferred. However, for many applications andespecially wherein low cost is a major consideration, incompletelypurified products can be employed since by-products of the reaction areoften unobjectionable.

The substituted styrene compounds employed as starting materials can beprepared in accordance with known or analogous methods. See, forexample, U.S. Pat. Nos. 3,391,203 and 3,336,401.

The following examples are presented to illustrate preparation oftypical compounds employed in the invention, but the scope of theinvention is not to be considered limited to the specific examplesgiven.

EXAMPLE 1

A buffer solution of 40% peracetic acid (24 milliliters; 0.160 mole) andsodium acetate trihydrate (2.0 grams; 0.025 mole) was added dropwisewith stirring to p-nitro-α-(2,2,2-trichloroethyl)styrene (12.0 grams;0.043 mole) dissolved in 75 milliliters of methylene chloride. Theaddition was carried out over a period of about 5-10 minutes and at atemperature of about 25° to about 35°C. Following the addition, thereaction mass was maintained at a temperature of about 35°C. for aperiod of about 16 hours, in order to assure substantial completion ofthe reaction. Upon completion of the reaction, the reaction mass waswashed with water to remove water-soluble impurities and neutralizedwith a sufficient amount of base, e.g., sodium carbonate. The reactionmass was again washed with water, dried over anhydrous sodium sulfate,and reduced to dryness by rotary evaporation. As a result of theseoperations, the 2-(p-nitrophenyl)-2-(2,2,2-trichloroethyl)oxiraneproduct was recovered as a yellow crystalline solid. Recrystallizationfrom chloroform gave the purified product as white plates having amelting point of 113°-114.5°C. Elemental analysis calculated for C₁₀ H₈Cl₃ No₃ (percent): C, 40.5; H, 2.7; N, 4.7. Found (percent) C, 40.1; H,2.7; N, 4.7.

EXAMPLES 2-33

Other representative products of the present invention, are prepared inaccordance with the procedures reported in Example 1 above, using therespective corresponding substituted styrene reactant and percarboxylicacid reactant. These other representative products corresponding to theformula below are identified in the following table. ##SPC4##

                  TABLE I                                                         ______________________________________                                        Ex.  Identity of Compound  Characterizing                                     No.  R        R'        X    Z     Property                                   ______________________________________                                         2   H        NO.sub.2  Cl   Cl    *M.W. 296.5                                 3   H        Br        Cl   Cl    *n.sub.D.sup.25 1.5735                                                         (88% pure)                                 4   H        CF.sub.3  Cl   Cl    *B.P. 86-88°C.                       5   Cl       Cl        Cl   Cl    B.P. 75°C. at                                                           0.5 mm Hg                                  6   H        Br        Cl   C.sub.2 H.sub.5                                                                     M.W. 324                                    7   H        Cl        Cl   Cl    n.sub.D.sup.25 1.5604                                                         (95% pure)                                  8   NO.sub.2 H         Cl   C.sub.4 H.sub.9                                                                     M.W. 318                                    9   H        CH.sub.3  Cl   Cl    B.P. 97°C.                          10   -CN      H         Cl   H     M.W. 242                                   11   CH.sub.3 O                                                                             H         Cl   Cl    M.W. 281.5                                 12   H        CH.sub.3 O                                                                              Cl   Cl    B.P. 98°C.                          13   H        CH.sub.3 O                                                                              F    -CN   M.W. 255.5                                 14   H        CH.sub.3 CH.sub.2 O                                                                     Cl   Cl    n.sub.D.sup.25 1.5475                                                          (90% pure)                                15   CH.sub.3 O                                                                             CH.sub.3 O                                                                              Cl   C.sub.3 H.sub.7                                                                     M.W. 319                                   16   H        C.sub.6 H.sub.5 CH.sub.2 O                                                              Cl   Cl    n.sub.D.sup.25 1.5703                                                          (61% pure)                                17   NO.sub.2 NO.sub.2  Br   C.sub.2 H.sub.5                                                                     M.W. 379.5                                 18   -CN      -CN       Cl   Cl    M.W. 301.5                                 19   H        F         Cl   Cl    M.W. 269.5                                 20   C.sub.3 H.sub.7                                                                        H         F    C.sub.2 H.sub.5                                                                     M.W. 270.5                                 21   C.sub.4 H.sub.9                                                                        C.sub.4 H.sub.9                                                                         Cl   Cl    M.W. 363.5                                 22   CH.sub.3 -CN       Cl   Cl    M.W. 290.5                                 23   NO.sub.2 C.sub.2 H.sub.5                                                                         Cl   C.sub.2 H.sub.5                                                                     M.W. 318                                   24   Br       Br        Cl   H     M.W. 375                                   25   CF.sub.3 H         Cl   Cl    M.W. 319.5                                 26   H        CF.sub.3  F    C.sub.3 H.sub.7                                                                     M.W. 310.5                                 27   C.sub.4 H.sub.9 O                                                                      H         Cl   Cl    M.W. 323.5                                 28   C.sub.4 H.sub.9 O                                                                      C.sub.4 H.sub.9 O                                                                       Cl   Cl    M.W. 395.5                                 29   Cl       H         Cl   Cl    B.P. 80°C.                          30   Br       H         Cl   Cl    M.P. 43.5-                                                                     44.5°C.                            31   C.sub.2 H.sub.5                                                                        H         Cl   -CN   M.W. 270                                   32   NO.sub.2 H         Cl   -CN   M.W. 287                                   33   H        CH.sub.3 O                                                                              Cl   -CN   M.W. 272                                   ______________________________________                                         *M.W. = Molecular Weight                                                      *B.P. = Boiling Point                                                         *n.sub.D.sup.25 = Refractive Index                                            *M.P. = Melting Point                                                    

Compounds of this invention are useful as pesticides. The mostdistinctive utility of the compounds is based upon their ability toinhibit the growth of objectionable plant life. This inhibition orherbicical activity may be demonstrated by contacting a plant structurewith the subject compounds, which may take place either pre-emergentlyor on established plants. Pre-emergence application may be accomplishedin either of two ways -- by application of the compounds to the surfaceof the soil or by incorporation of the compounds into the surface layerof soil. In addition to herbicidal activity, some of the compounds ofthis invention possess activity as fungicides. Some of the compoundspossess multiple activity in two or more of the above mentioned areas.Hence the user may benefit from the application of these compounds in adual or multiple manner, depending upon which compound or mixture ofcompounds is selected. Accordingly, the term pesticidal activity refersto a toxic activity in one or more of the above areas of herbicidal orfungicidal activity.

In particular, it has been discovered that undesirable plants and fungalorganisms can be controlled by contacting such plants or organismsand/or their habitats with compositions containing an effectivegrowth-controlling amount of at least one of the oxirane compoundsdisclosed herein. Complete control and kill of various fungal organismsis obtained when such organisms are contacted with compositionscontaining at least one of the oxirane compounds in dosages sufficientto supply from about 100 to about 1000 or more parts by weight ofcompound per million parts of ultimate treating composition. When thegerminant seeds and emerging seedlings of many terrestrial plant speciesare contacted with compositions containing one of the oxirane compoundsin dosages sufficient to supply from about 1.0 to about 50.0 pounds ofthe compound per acre, a persistent inhibition of the growth of suchseeds and seedlings is obtained.

In selective applications to plants and/or their habitats for thepre-emergent control of the germinant seeds and seedlings of manyundesirable plants, especially those of small-seeded grasses in areasplanted with the seeds of desired broadleaf plants or supporting thegrowth of such plants, compositions containing certain of the oxiranecompounds in dosages of from about 0.03 to about 0.5 pounds or more ofthe oxirane compound per acre have been found satisfactory. Theapplication of larger dosages to terrestrial plants and/or theirhabitats controls the growth of germinant seeds, of all types, includingbroadleaf plants, as well as grasses. In all selective applications, theexact dosage to be employed is dependent upon the resistance of thebroadleaf crop plants or their seeds to the particular oxiranecomposition employed and related factors.

It has also been found that compositions employing certain of theoxirane compounds of dosages of from about 250 to about 4000 or moreparts by weight per million parts of ultimate treating composition areeffective in controlling the growth of the established plants of manyplant species. In many instances, the application of the compositionscontaining certain oxirane compounds in dosages of from about 250 toabout 1000 parts per million by weight per million parts of treatingcomposition results in the selective post-emergent control of manyundesirable plant species, especially those of small-seeded grasses inareas supporting the growth of the established plants of desired cropplants, e.g., cotton, corn, cultured rice and white winter wheat. In allselective operations, the exact dosage to be employed is dependent uponthe resistance of the crop plants to the particular oxirane compositionemployed and other related factors apparent to those skilled in the art.

The application to plants, plant-parts and/or their habitats of acomposition containing a growth-suppressing amount of an oxiranecompound is essential and critical for the practice of the presentinvention. The exact dosage to be supplied by the composition in a givenoperation is dependent upon the fungal and plant species and the stageof growth and hardiness thereof as well as the plant part to be exposedto the pesticidal composition. Other factors, such as, for example, theweather conditions of temperature and moisture, the weathering action ofsun and rain, the possibly the decomposition of the compositions and theoxirane compounds contained therein by the action of bacterial and othersoil organisms which eventually frees the plant, plant part, and/ortheir habitats of the composition must also be considered. Thus, whilethe application of low amounts of active compounds per acre may besufficient for good control of a light infestation of weeds growingunder adverse conditions, applications of from 5 to 10 pounds or more ofactive compound per acre may be required for good control of a denseinfestation of hardy weeds growing under favorable conditions.

Compositions comprising an oxirane compound and a liquid or solidcarrier allow the growth-suppressing amount of the active agent to bemixed in such quantity of ultimate treating material that adequatecoverage of all plants and plant-parts or adequate admixture with theirhabitats (e.g., soil) can be obtained. Good growth-suppressing resultsare obtained when employing a carrier material in relatively small, buteffective amounts. Generally, however, the best results are obtained byemploying either a suface-active dispersing agent, in an amountsufficient to emulsify the oxirane compound with water as a carrier, forexample, an amount which represents from 0.1 to 15 percent, by weight,of the total treating material; or a finely divided carrier solid, in anamount which represents from 40 to 99.5 percent, by weight, of the totaltreating material.

The exact concentration of the oxirane compounds employed in thecompositions for application to plants, plant-parts and/or theirhabitats is not critical and can vary considerably provided the requireddosage of effective agent is supplied on the plant, plant-part and/orhabitat treated. The concentration of the oxirane compound in liquidcompositions employed to supply the desired dosage generally is fromabout 0.0001 to about 50 percent by weight, although concentrations ashigh as 90 percent by weight are sometimes conveniently employed. Infinely divided solid carrier compositions, the concentration of theoxirane compound can be from 0.1 to 60 percent by weight. Incompositions to be employed as concentrates, the oxirane compound can bepresent in a concentration of from 5 to 98 percent by weight.

The quantity of treating compositions to be applied can varyconsiderably provided that the required dosage of active ingredient isapplied in sufficient of the finished composition to facilitate thedistribution of the active agent on the plant or plant-part, or thepenetration of the active agent in the plant habitat. The requiredamount of the active agent conveniently can be supplied per acre treatedin from 10 to 27,000 gallons or more of the liquid carrier or in from 10to 2,000 pounds of the finely divided solid carrier.

Liquid compositions containing the desired amount of active ingredientcan be prepared by dissolving the oxirane compound in an organic liquidcarrier or by dispersing the oxirane compound in water with or withoutthe aid of a suitable surface-active dispersing agent such as an ionicor non-ionic emulsifying agent. Suitable organic liquid carriers includethe agricultural spray oils and the petroleum distillates such as dieselfuel, kerosene, fuel oil, naphthas and Stoddard solvent. Among theorganic liquid carriers, the petroleum distillates are generallypreferred. The aqueous compositions can contain one or more waterimmiscible solvents for the oxirane compound. In such compositions, thecarrier comprises an aqueous emulsion, i.e., a mixture of water,emulsifying agent and water immiscible solvent. The choice of dispersingand emulsifying agent and the amount thereof employed is dictated by thenature of the composition and by the ability of the agent to facilitatethe dispersion of the oxirane compound in the carrier to produce thedesired composition. Dispersing and emulsifying agents which can beemployed in the compositions include the condensation products ofalkylene oxides with phenols and organic acids, alkyl aryl sulfonates,polyoxyalkylene derivatives of sorbitan esters, complex ether alcohols,mahogany soaps, and the like.

In the preparation of dust compositions, the active ingredient isdispersed in and on a finely divided solid carrier such as clay, talc,chalk, gypsum, bentonite, fuller's earth, attapulgite, and the like. Insuch operation, the finely divided carrier is mechanically mixed orground with the oxirane compound. Depending upon the proportion ofingredients, these dust compositions can be employed as concentrates andsubsequently diluted with additional solid carrier or with liquid orsolid surface-active dispersing agent to obtain the desired amount ofactive ingredient in a composition adapted to be employed for thesuppression of the growth of the plants. Also, such dust compositionscan be dispersed in water, preferably with the aid of a surface-activedispersing agent, to form spray mixtures.

Satisfactory results are obtained when the oxirane compositions arecombined with other agricultural materials intended to be applied toplants, plant-parts, and/or their habitats. Such materials includefertilizers, fungicides, insecticides, soil conditioning agents, and thelike.

When operating in accordance with the present invention, compositionscontaining growth-suppressing amounts of the oxirane compounds areapplied to plants, plant-parts and/or their habitats in any convenientfashion. Applications to a plant habitat, e.g., soil, can be carried outby simply mixing with the habitat, such as by applying to the surface ofsoil and thereafter dragging or discing into the soil to the desireddepth or by employing a liquid carrier to accomplish the penetration andimpregnation. The application of spray and dust compositions to thesurface of soil can be carried out by conventional methods, e.g., powerdusters, boom and hand sprayers and spray dusters.

In a further method, the distribution of the oxirane compositions insoil can be accomplished by introducing the agent in the water employedto irrigate the soil. In such procedures, the amount of water can bevaried with the porosity and water holding capacity of the soil toobtain a desired depth of distribution of the agent.

Other components of the habitat of a plant can be employed in thetransfer of the agent of the present invention to a plant or plant part.

In addition, the present method also comprehends the employment of anaerosol composition containing an oxirane compound as an activecompound. Such a composition is prepared according to conventionalmethods wherein the active ingredient is dispersed in a solvent, and theresultant dispersion mixed with a propellant in liquid state. Suchvariables as the paticular active ingredient to be used and theparticular plant part to be treated will determine the identity of thesolvent and the concentration of the active ingredient therein. Examplesof suitable solvents are water, acetone, isopropanol, and2-ethoxyethanol. Also, employment of the oxirane compound in pastes,gels, foams, invert emulsions, and the like, as well as pigmented orunpigmented pelleted solids is comprehended.

The following examples further illustrate the present invention.

EXAMPLE 34

Separate aqueous compositions containing2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane,2-(p-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane,2-(m-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane, and2-(p-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane were prepared asfollows:

Four parts by weight of the compound, 0.08 part of sorbitan trioleate(Span 85), and 0.02 part of a sorbitan monooleate polyoxyethylenederivative (Tween 80) are dispersed in 40 milliliters of acetone toproduce a concentrate composition in the form of a water-dispersibleliquid containing the predetermined oxirane compound as the sole activeagent.

A portion of each of these concentrate compositions were separatelydispersed in portions of water to provide aqueous compositions,containing 0.44 pound of the oxirane compound per 100 gallons ofultimate aqueous mixture.

The aqueous compositions were then employed for the treatment of seedbeds of good agricultural soil which had been prepared and seeded withthe seeds of various grass species and broadleaf plants. The grassspecies included white winter wheat, cultured rice, pigweeds, crabgrass,cheat grass, wild oats, Johnson grass, barnyard grass and yellowfoxtail; and the broadleaf plants included corn. In the treatingoperations, a predetermined quantity of each of the compositions wasapplied to separate seedbeds as a soil drench at a rate of about 0.43acre inch of aqueous composition per acre. The quantities werecontrolled to supply a substantial uniform dosage in a seedbedequivalent to 1.0, 2.0 and 5.0 pounds of the oxirane compound per acre.These dosages correspond, respectively, to a concentration, within thesoil depth penetrated of about 1.6, 3.2 and 8.0 parts by weight of theoxirane compound per million parts by weight of soil. Other seedbedswere similarly seeded with the named plant species but were leftuntreated to serve as checks.

After about 2 weeks the seedbeds were examined to acertain what controlof the growth of seeds had been obtained. The results are set forth inthe following Table II.

                                      Table II                                    __________________________________________________________________________    Percent Pre-Emergent Control of Seed Germination at Various                   Indicated Toxicant Concentrations (in Pounds per Surface Area)                              2-(m-bromophenyl)-                                                                        2-(p-bromophenyl)-                                                                        2-(m-nitrophenyl)-                                                                        2-(p-chlorophenyl)-         2-(2,2,2-trichloro-                                                           2-(2,2,2-trichloro-                                                           2-(2,2,2-trichloro-                                                           2-(2,2,2-trichloro-                                                           Seed Species  ethyl)oxirane                                                                             ethyl)oxirane                                                                             ethyl)oxirane                                                                             ethyl)oxirane               __________________________________________________________________________                                                      1                                         1.0 2.0 5.0 1.0 2.0 5.0 1.0 2.0 5.0 1.0 2.0 5.0                 1.  Pigweeds  95  100 100 50  50  90  85  95  95  50  100 100                 2.  Crabgrass 0   100 100 0   100 100 95  100 100 95  100 100                 3.  Johnson Grass                                                                           95  95  100 95  95  95  70  85  95  95  100 100                 4.  Barnyard Grass                                                                          95  95  95  95  95  95  50  50  95  95  95  100                 5.  Wild Oats 100 100 100 95  95  90  40  50  80  100 100 100                 6.  Cheat Grass                                                                             --  --  --  --  --  --  --  80  100 --  --  --                  7.  Cultured Rice                                                                           --  100 100 --  100 100 100 95  100 100 100 100                 8.  Yellow Foxtail                                                                          100 100 95  0   0   80  100 --  --  95  95  95                  9.  White Winter                                                                   Wheat    100 100 100 95  95  95  95  50  95  95  100 100                 10. Corn      30  95  95  0   50  95  100 50  0   85  95  95                  __________________________________________________________________________     At the time of the observations, the check areas showed populous and          vigorous growing stands of the named plant species.                      

EXAMPLE 35

Aqueous compositions containing one of each of the following compounds:

2-(m-tolyl)-2-(2,2,2-trichloroethyl)oxirane;

2-(m-methoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane;

2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane;

2-(m-fluorophenyl)-2-(2,2,2-trichloroethyl)oxirane;

2-(3,4-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane;

2-(m-ethoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane; and

2-(m-(benzyloxy)phenyl)-2-(2,2,2-trichloroethyl)oxirane

were prepared as in Example 34 and similarly employed for thepre-emergence treatment of various plant species.

As a result of such operations, it was found that the2-(m-tolyl)-2-(2,2,2-trichloroethyl)oxirane compound gave substantiallycomplete control of pigweeds, crabgrass, Johnson grass, barnyard grass,wild oats and yellow foxtail when the seeds of such species werecontacted with compositions containing the active compound in amountssufficient to supply a dosage of 2.0 pounds per acre.

In other similar operations, the2-(m-methoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane compound gavesubstantially complete pre-emergence control of pigweeds, crabgrass,Johnson grass and barnyard grass and the2-(m-ethoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane compound gavesubstantially complete control of crabgrass, Johnson grass, barnyardgrass and wild oats when the seeds of such plant species were contactedwith compositions containing the respective active compounds in amountssufficient to supply a dosage of 2.0 pounds per acre.

In further pre-emergence operations, the2-(m-(benzyloxy)phenyl)-2-(2,2,2-trichloroethyl) oxirane compound gavesubstantially complete control of pigweed, crabgrass, barnyard grass,wild oats and yellow foxtail when the seeds of such species werecontacted with sufficient composition to supply a dosage of 20 poundsper acre.

The treatment of the seeds of pigweeds, crabgrass, Johnson grass andwild oats with a composition containing the2-(3,4-dichlorophenyl)-2-(2,2,2-trichloroethyl)-oxirane compound at arate of 2.0 pounds per acre likewise gave substantially complete controlof the species.

Substantially complete pre-emergence control of crabgrass, Johnsongrass, barnyard grass, wild oats and yellow foxtail was also obtained bythe application of compositions containing2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane and2-(m-fluorophenyl)-2-(2,2,2-trichloroethyl)oxirane, respectively, atdosage rates of 0.25 and 0.5 pounds per acre, respectively.

EXAMPLE 36

Separate aqueous compositions containing the2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane (Cmpd. A) and2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane (Cmpd. C) compounds ofthe present invention were prepared as in Example 34 for comparativepre-emergence herbicide tests against noxious grass species with theknown 2-(p-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane (Cmpd. B)compound and 2-(p-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane (Cmpd.D). The pre-emergence tests were conducted as in Example 34 and theresults of such tests are set forth below in Table III.

                  Table III                                                       ______________________________________                                        Cmpd.    Rate         % Control                                                             Water-  Crab       Johnson                                      Lb/Acre       Grass   Grass      Grass                                        ______________________________________                                        A       1. 1/8    90      100      100                                                2. 1/16   85      100      100                                        B       1. 1/8    90      20       30                                                 2. 1/16   60       0        0                                         C       1. 1/8    95      95       95                                                 2. 1/16   90      70       95                                         D       1. 1/8    60       0       25                                                 2. 1/16   30       0        0                                         ______________________________________                                    

At the same low dosage rates as set forth in the above table, nopre-emergence effect on the seeds of cotton and corn plants wasobserved.

EXAMPLE 37

An aqueous composition containing 2-(α,α ,α-trifluoro-m-tolyl)-2-(2,2,2-trichloroethyl)oxirane was prepared asdescribed in Example 34. The composition was then employed according tothe procedures of Example 34 except that lower concentrations of theoxirane compound were employed in the composition.

The percent control of the various plant species at the employed dosagerate of the 2-(α,α ,α -trifluoro-m-tolyl)-2-(2,2,2-trichloroethyl)supplied by the composition is set forth in the following Table IV.

                                      Table IV                                    __________________________________________________________________________    Percent Pre-Emergent Control of Seed                                          Germination at Various Indicated Concentra-                                   tions (in Pounds per Surface Area)                                            Seed Species 0.03                                                                              0.07                                                                              0.13                                                                              0.25                                                                              0.5 1.0                                          __________________________________________________________________________    1.  Pigweeds 0   30  50  100 100 100                                          2.  Crabgrass                                                                              60  75  100 100 100 100                                          3.  Johnson                                                                        Grass   0   80  100 100 100 100                                          4.  Barnyard                                                                       Grass   50  95  95  95  95  95                                           5.  Wild Oats                                                                              30  85  95  95  95  95                                           6.  Yellow                                                                         Foxtail 30  0   95  100 100 100                                          7.  Soybeans 0   0   100 40  50  60                                           8.  Cotton   0   0   0   0   30  20                                           9.  White Winter                                                                   Wheat   0   50  100 100 100 100                                          10. Corn     0   0   0   90  95  95                                           11. Beans    30  30  30  60  70  95                                           12. Cultured Rice                                                                          0   30  100 100 100 100                                          __________________________________________________________________________     At the time of the observations, the check areas showed populous and          vigorous growing stands of the named plant species.                      

EXAMPLE 38

An aqueous composition containing2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane was prepared asdescribed in Example 34. Separate portions of this composition werethereafter dispersed in a further quantity of water to prepare aqueousspray compositions containing 250, 500, 1000, 2000, and 4000 parts,respectively, of the compound per million parts by weight of ultimatetreating composition. These compositions were applied as foliage spraysto various grass and broadleaf plant species, the plants being of 2 to 4inches in height and growing in seed beds. The treatments were carriedout with conventional spray equipment, the plants being sprayed to thepoint of run-off. Similar beds of the plant species were left untreatedto serve as checks. After about two weeks, the beds were examined toascertain what control of the growth of plants had been obtained. Theplant species employed, together with the percent control obtained atthe employed dosage rate of the composition is set forth in thefollowing Table V.

                  Table V                                                         ______________________________________                                        Percent Post-Emergent Control of Seed                                         Germination at Various Indicated                                              Concentrations                                                                Seed Species   250    500    1000  2000  4000                                 ______________________________________                                        1.    Crabgrass    30     65   95    95    95                                 2.    Johnson Grass                                                                              95     95   95    95    95                                 3.    Barnyard Grass                                                                             95     95   95    95    95                                 4.    Yellow Foxtail                                                                             40     95   95    95    95                                 5.    Soybean      30     30   50    75    85                                 6.    Cotton       0      0    50    50    65                                 7.    White Winter                                                                   Wheat       0      0    50    50    50                                 8.    Corn         0      30   50    95    95                                 9.    Pinto Beans  50     50   50    75    75                                 10.   Wild Oats    50     70   85    85    95                                 11.   Cultured Rice                                                                              0      0    0     40    50                                 ______________________________________                                         At the time of the observations, the check areas showed populous and          vigorous growing stands of the named species.                            

EXAMPLE 39

Separate acetone compositions containing 100 and 500 parts,respectively, of each of2-(p-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane and2-(m-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane compounds per millionparts by weight of ultimate mixture were prepared by dissolving apre-determined amount of each of the above comounds in acetone to givethe desired concentrations. The solutions were dispersed in meltednutrient agar to produce culture media for fungal plants. The agarsolutions were poured into petri dished and allowed to solidify. Thesolidified agar surface in each petri dish was inoculated with onespecies of a fungal plant; the plants employed being Staphylococcusaureus, Candida albicans, Tichophton mentagrophytes, Bacillus subtilis,Aspergillus terreus, Candida pelliculosa, Pullularia pullulans,Mycobacterium phlei, Cephaloascus fragans and Aerobacter aerogenes.

The inoculation was carried out by applying droplets of a solutioncontaining the fungal plants to the agar surfaces. The inoculated petridishes were then incubated for an appropriate period of time and underconditions conducive to the growth of the fungal plants involved.

After incubation, the petri dishes were examined to determine the degreeof control of the fungal plants. In these operations, it was found thatthe composition containing 100 parts per million by weight of the2-(p-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane compound gave completecontrol and kill of Bacillus subtilis and Aerobacter aerogenes. Thecomposition containing 500 parts by weight of 2-(m-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane gave complete controland kill of Staphylococcus aureus, Candida albicans, Trichophtonmentagrophytes, Bacillus subtilis, Aspergillus terreus, Candidapelliculosa, Pullularia pullulans, Mycobacterium phlei and Cephaloascusfragans.

In similar operations, it was found that compositions containing 500parts per million by weight of composition of one of each of thefollowing compounds:

2-(m-tolyl)-2-(2,2,2-trichloroethyl)oxirane;2-(m-methoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(m-fluorophenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(3,4-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(m-ethoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(m-(benzyloxy)phenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(p-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane;2-(p-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane; and2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane gave complete controland kill of Trichophyton mentagrophytes, Bacillus subtilis andMycobacterium phlei.

What is claimed is:
 1. A method for controlling undesirable plants whichcomprises applying thereto an effective herbicidal amount of asubstituted oxirane compound corresponding to the formula:##SPC5##wherein X represents halogen; Z represents hydrogen, halogen,cyano or lower alkyl; R and R' each independently represent hydrogen,halogen, cyano, nitro, alkoxy of from 1 to 4 carbon atoms,trifluoromethyl, benzyloxy or lower alkyl, with the proviso that when R'is hydrogen, R is other than hydrogen.
 2. A method according to claim 1wherein said oxirane compound is applied to soil containing seeds ofundesired plants.
 3. A method according to claim 1 wherein said oxiranecompound is applied to established plants.
 4. A method according toclaim 1 wherein R is hydrogen.
 5. A method according to claim 1 whereinR and R' each independently represent hydrogen, halogen, nitro,trifluoromethyl, lower alkoxy or lower alkyl, with the proviso that whenR' is hydrogen, R is other than hydrogen.
 6. A method according to claim1 wherein R is hydrogen and R' is halogen or trifluoromethyl.
 7. Themethod of claim 1 wherein the compound is2-(m-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 8. The method ofclaim 1 wherein the compound is2-(p-nitrophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 9. The method ofclaim 1 wherein the compound is 2-(α,α ,α-trifluoro-m-tolyl)-2-(2,2,2-trichloroethyl)oxirane.
 10. The method ofclaim 1 wherein the compound is2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 11. The method ofclaim 1 wherein the compound is2-(p-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 12. The method ofclaim 1 wherein the compound is2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 13. The method ofclaim 1 wherein the compound is2-(p-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 14. The method ofclaim 1 wherein the compound is2-(m-fluorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 15. The method ofclaim 1 wherein the compound is2-(3,4-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 16. The methodof claim 1 wherein the compound is2-(m-tolyl)-2-(2,2,2-trichloroethyl)oxirane.
 17. The method of claim 1wherein the compound is2-(m-methoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane.
 18. The method ofclaim 1 wherein the compound is2-(m-ethoxyphenyl)-2-(2,2,2-trichloroethyl)oxirane.
 19. The method ofclaim 1 wherein the compound is2-(m-(benzyloxy)phenyl)-2-(2,2,2-trichloroethyl)oxirane.
 20. The methodaccording to claim 1 wherein R and R' each independently representhydrogen, halogen, trifluoromethyl or lower alkyl, with the proviso thatwhen R' is hydrogen, R is other than hydrogen.
 21. A method for theselective control of weedy grasses in the presence of desirable cropswhich comprises applying to soil containing desirable crops before theplants to be destroyed emerge in a concentration toxic to weedy grasses,but not toxic to desirable crops, a compound of the formula##SPC6##wherein X represents halogen; Z represents hydrogen, halogen,cyano or lower alkyl; R represents hydrogen and R' is halogen ortrifluoromethyl.
 22. The method of claim 21 wherein R' is halogen. 23.The method of claim 2 wherein the compound is2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 24. The method ofclaim 21 wherein the compound is2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 25. The method ofclaim 21 wherein the compound is 2-(α,α ,α-trifluoromethyl-m-tolyl)-2-(2,2,2-trichloroethyl)oxirane.
 26. Aherbicidal composition which comprises an inert carrier and as theactive agent a herbicidally-effective amount of a compound of theformula: ##SPC7##wherein X represents halogen; Z represents hydrogen,halogen, cyano or lower alkyl; R and R' each independently representhydrogen, halogen, cyano, nitro, alkoxy of from 1 to 4 carbon atoms,trifluoromethyl, benzyloxy or lower alkyl, with the proviso that when R'is hydrogen, R is cyano, nitro, alkoxy, trifluoromethyl, benzyloxy orlower alkyl.
 27. The composition of claim 26 wherein R representshydrogen and R' represents halogen or trifluoromethyl.
 28. Thecomposition according to claim 26 whrein R and R' each independentlyrepresent hydrogen, halogen, trifluoromethyl or lower alkyl, with theproviso that when R' is hydrogen, R is other than hydrogen.
 29. Thecomposition of claim 26 wherein the compound is2-(m-chlorophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 30. The compositionof claim 26 wherein the compound is2-(m-bromophenyl)-2-(2,2,2-trichloroethyl)oxirane.
 31. The compositionof claim 26 wherein the compound is 2-(α,α ,α-trifluoromethyl-m-tolyl)-2-(2,2,2-trichloroethyl)oxirane.
 32. Aqueousdispersion of the composition claimed in claim 26, the oxirane compoundin such dispersion being present in a herbicidal amount of at least0.0001 percent by weight.
 33. The composition of claim 26 in intimateadmixture with an inert finely divided solid, the oxirane compound insuch admixture being present in a herbicidal amount of from 0.1 to 60percent by weight.